The present invention relates to a method and means for controlling the amount of size applied to a traveling textile substrate, and more particularly to such a method and means in which the size is applied to a traveling textile substrate in a size applicator in which the substrate is passed through a size bath and squeeze rollers with the squeezing pressure being regulated as a function of the speed of the substrate.
In industrial use of size applicators it is the intended purpose to apply a uniform optimum amount of sizing to the textile substrate, such as yarn, independent of the speed of travel of the textile substrate. The amount of sizing applied is conventionally controlled by regulating the squeezing pressure of the squeezing unit. When the speed of the traveling textile substrate is changed i.e. from normal running speed to a slow speed, the regulating device changes the squeezing pressure. To maintain a constant size pick-up, a high squeezing pressure is applied when the traveling textile substrate, such as a sheet of warp yarns, is traveling at normal operating high speed, and a relatively low squeezing pressure is applied when the speed of the traveling substrate is reduced. This control of the squeezing pressure as a function of the speed of travel, does not necessarily result in a uniform pick-up. Attempts have been made to enhance control by taking actual measurements of the substrate through infra-red, micro-wave or beta-ray devices. However, despite the substantial expense of such sophisticated devices, acceptable reliability of results has not been obtained. Rather, at the present time the uniformity of size application depends largely on the ability and experience of the operators.